There's only 200 pixels height in the GUI; but I really see that as no problem. Space Invaders is a perfect candidate for pushing the data sections off to the side. With that, there'd still be enough room for a game menu (hidden during game play), while maintaining all the exact arcade vertical spacings -- which is not the case for the 100% vertical layout I did above.
"No benefits to be had running it in a GUI"? I guess you mean no advantage over what could be accomplished graphically in a non-GUI version, with full control over the screen, DLI's, etc. (like I was demonstrating above); agreed there; but, they'll be plenty of other benefits to having games available in the GUI, such as multitasking (paused game in the background waiting), standardized menus and dialogue boxes (for options, etc.), mouse control (for menus and dialogues, etc.)... and hi-res games are an obvious prime target.